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OEM Carrier 40VA 120V to 24V Control Transformer for C48A303552 | National HVAC Parts
Carrier

OEM Carrier 40VA 120V to 24V Control Transformer for C48A303552 | National HVAC Parts

SKU: CARRIE-C48A303552-TRANSFORMER-HT01BD236 Brand: Carrier
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OEM Carrier Control Transformer 40VA for Model C48A303552

This OEM Carrier transformer (part number HT01BD236) is the factory-specified step-down transformer for the Carrier C48A303552 packaged unit. The transformer converts 120V line voltage to the 24V AC signal that powers the entire control circuit — including the thermostat, contactor coil, gas valve, and control board. When this transformer fails, the entire control system goes dark: the thermostat loses power, nothing responds, and the unit will not start at all. It is one of the first components to check when diagnosing a completely unresponsive system.

  • Specs: 40VA rating | Primary: 120V AC | Secondary: 24V AC | OEM part number HT01BD236 | Factory-matched output for Carrier packaged equipment control circuits
  • OEM vs Generic: This OEM transformer is wound to exact Carrier factory specifications, ensuring stable 24V output under full load. Generic transformers often underperform at rated VA, causing nuisance lockouts, erratic thermostat behavior, or premature contactor coil failure due to undervoltage.
  • Install difficulty: 2/5 — Disconnect all power before servicing. Tools needed: flathead and Phillips screwdrivers, needle-nose pliers, multimeter. Always verify 0V at the transformer primary terminals before touching any wiring. Label all low-voltage leads before disconnecting.
  • Warranty: 1-year OEM factory warranty. Leaves our warehouse the same business day when ordered before cutoff.

Compatibility: Designed for the Carrier C48A303552 packaged unit. Verify your existing transformer's VA rating and primary/secondary voltages on the unit data plate or wiring diagram before ordering. Our HVAC parts specialists are available to confirm fitment — order with confidence and get back up and running fast.

Shipping Information

  • Orders placed before 3PM CST ship same business day
  • Standard delivery: 2-5 business days
  • Express shipping available at checkout
  • Free shipping on orders over $99
  • Tracking number emailed upon shipment

Return Policy

  • 30-day returns on unused parts in original packaging
  • Electrical parts (capacitors, contactors, control boards) are final sale once installed
  • Email info@nationalhvacparts.com to initiate a return
  • Refunds processed within 5-7 business days

Frequently Asked Questions

Does this Transformer fit my Carrier C48A303552 | National HVAC Parts?
Yes. This is the factory-specified OEM transformer for the Carrier C48A303552 | National HVAC Parts. It is a direct drop-in replacement that fits without modification. Always verify the model number on your equipment nameplate before ordering.
How do I replace the transformer on my Carrier C48A303552 | National HVAC Parts?
Difficulty: Medium (30–45 min)
Step 1: Turn off breaker. Step 2: Photo wiring connections. Step 3: Disconnect wires from old transformer. Step 4: Remove mounting hardware. Step 5: Install new transformer, reconnect wires matching voltage ratings. Step 6: Verify 24V output with multimeter.
My thermostat has no power. What failed?
Thermostat with no display = failed 24V transformer (or blown control board fuse). Check the 3A/5A fuse on the control board first ($1–$5 fix). If fuse is good but no 24V output from transformer, replace transformer.
Is this transformer compatible with Bryant or Payne too?
Many Carrier parts are cross-compatible with Bryant and Payne since all three brands are manufactured by Carrier Global Corporation. The same physical part is often used across brand labels with different model numbers. To verify: check your Bryant or Payne equipment service manual for cross-compatible part numbers, or email info@nationalhvacparts.com with your model number.
Should I use OEM or aftermarket for my Carrier transformer?
OEM recommended for reliability and warranty compatibility. OEM parts match exact factory specifications for proper fit, performance, and safety. While aftermarket alternatives cost less upfront, the risk of improper fit and reduced lifespan usually makes OEM the better value long-term.
How fast does National HVAC Parts ship?
Orders placed before 3:00 PM CST ship the same business day. Standard delivery is 2–5 business days anywhere in the continental United States. Express shipping available at checkout. We ship from Houston, TX to all 50 states. 30-day return policy on all parts.
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Mike Rivera
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